Alvan L. Barach

Effect of Inhalation of High Oxygen Concentrations, With and Without Carbon Dioxide, on the Electrocardiogram

Summary Inhalation of 100% oxygen has been shown to result in the elevation of the T wave in the electrocardiogram in 20 of 26 cardiac cases, and in 2 of a group of 8 normal and miscellaneous cases. When 97 or 96% oxygen with 3 or 4% carbon dioxide was tested, similar electrocardiographic changes were observed although the degree of change was frequently less marked; thus, in 7 of 20 cardiac cases the T wave was distinctly more elevated after inhalation of 100% oxygen than after the oxygen-carbon dioxide mixture. The significance of these observations is discussed. It seems likely that inhalation of 100% oxygen shortens the recovery period of cardiac muscle.

Horizontal Respiratory Graphs by Automatic Feed of Oxygen into a Basal Metabolism Apparatus

Summary The levelling device described makes it possible to record horizontal respiratory graphs by means of a continuous inflow of oxygen, automatically regulated to correspond to the patients oxygen consumption. Any gas mixture desired may be kept constant during the test period since the oxygen concentration in the basal metabolism circuit remains within ±0.5% of the original concentration. With the use of an auxiliary recording spirometer, it is possible to record oxygen consumption and respiratory tracings simultaneously. Oxygen deficit may be acctlrately recorded.

Treatment of pulmonary emphysema and cor pulmonale with anti-inflammatory steroids.

Restoration of compensation has been induced by oxygen therapy in some cases of intractable cardiac failure, including those with cor pulmonale and pulmonary emphysema, as well as in those with left ventricular insufficiency. Improved heart action and an increased excretion of chlorides (associated with COz elevation in the blood and tissues) have been considered significant factors in the initiation of diuresis by oxygen A diuretic response to administration of steroids has also been observed in some cases of heart failure that were refractory to routine Camara and Schemm4 used corticotropin in the production of diuresis in patients with refractory heart failure, and Riemera reported a similar result with prednisone in a patient with multiple myocardial infarctions and intractable cardiac decompensation. In our clinic, the use of prednisone was followed by prompt weight loss and increased urinary output in cases of pulmonary emphysema and fibrosis with cor pulmonale and in those without cardiac f a i l ~ r e . ~ The therapeutic activity of corticosteroids in the control of refractory cardiac failure may depend in part on a diuretic action that results from their ability to increase the glomerular filtration rate.? The steroid compounds may maintain the structural integrity of capillaries and hence prevent fluid loss from the intravascular spaces; the consequent increase in plasma volume may augment the glomerular filtration rate and thereby promote diuresis. The diuretic effect was found to be more marked in the delta-1 compounds, such as prednisone, than in the cortisone-hydrocortisone compounds that have an antagonistic sodium-retaining action. Riemer? suggested that steroids could exert their diuretic action by suppressing the output of other adrenocortical steroids, such as aldosterone, and thereby inhibit the sodium retention caused by the excess of aldosterone that may occur in heart failure. There is evidence that steroids also have inhibitory actions against pituitary antidiuretic hormone.10 A special effect of the use of steroids in cases of chronic pulmonary disease with cor pulmonale or left heart failure is the conspicuous relief of hypoxia resulting from improvement in alveolar ventilation. In such clinical entities as pulmonary emphysema and fibrosis and severe bronchial asthma, the administration of anti-inflammatory steroids presumably is followed by a reduction in edema of the bronchial mucous membrane as well as by relief of bronchospasm, increase in the patency of the airway, and a consequent rise in arterial oxygen tension.11-12 In cases of cor pulmonale, Dexter et showed that, when hypoxia is absent, the cardiac output decreases in inverse relationship to the degree of pulmonary hypertension, and heart failure is rare; in the presence of hypoxia, the cardiac output rises. Cardiac failure depends on the association of hypoxia with a high degree of pulmonary resistance and occurs when the right ventricular myocardium is unable to raise the output, presumably because of poor oxygen supply. The administration of oxygen is a specific measure for the correction of these disturbances. The correction of hypoxia

A Method for Obtaining Gas Samples of the Total Inspired Air

Conclusions A method for obtaining an accurate mixed sample of the total inspired air is described. Provision is made for control of the size of the sample and the rate of sampling so that they conform to the inspired air of the subject. The CO2 percentage of the inspired air in a mask is more reliably obtained through this method than through alveolar CO2 samples, since the volume of ventilation tends to keep the CO2 tension constant. Alveolar samples taken at low barometric pressures, such as 140 mm Hg, are compressed to such a small volume at sea level that analysis may be difficult. Such difficulty is not experienced when taking large inspired air samples for analysis.